Chinese star judoka Tong Wen's bid for her second straight Olympic gold medal was thwarted on Friday as she suffered a shock defeat in the semifinals on the last day of the judo competition.

Tong beat Brazilian Maria Suelen Altheman in the bronze medal fight with an ippon.

Tong beat Brazilian Maria Suelen Altheman in the bronze medal fight with an ippon, her fourth in five matches.

But a lapse in the semifinals cost Tong a chance of defending her +78kg Olympic title and sent Cuban Idalys Ortiz to the final.

Ortiz, the bronze medalist in Beijing Games, then defeated Japanese Mika Sugimoto to win gold.

"China won three gold medals in judo four years ago. This time the team lay hopes on me, so I feel much pressure, which prevented me from delivering my potential," said the 29-year-old Tong.

Karina Bryant of Britain bagged a bronze, the hosts' second medal in judo events here after Gemma Gibbons gave her nation a silver in the women's -78kg judo.

In the men's +100kg event, Beijing Games bronze medalist Frenchman Teddy Riner, a four-time world champion, defeated Russian Alexander Mikhaylin to take the title.

Rafael Silva of Brazil and Andreas Toelzer of Germany shared the bronze.

There were six defending champions competing in London, but none succeeded.